Study on the demagnetization process of the hot rolled medium carbon steel

Abstract

Residual magnetism is always of presence in the medium carbon steel formed in the hot rolling process even by the traditional demagnetization treatment. In order to eliminate the residual magnetism in the typical medium carbon steel, the steel was annealed at 650℃ for different holding time. It is found that, at the early stage of the annealing process, the residual magnetism in the steel decreases gradually with increasing the annealing time. When the annealing time reaches 60 min., The removed residual magnetism reaches a peak. It is attributed to the dissolution and the spheroidization of carbide structure during the annealing process, and the decrease of the micro-strain in the steel, as well. When the annealing time increased from 60 min. to 75 min., the residual magnetism increases with increasing the annealing time for the formation of the heterogeneous microstructure in the steel.